Distronic Plus doesn't always activate?
 

Just got my 2016 C350e which is equipped with Distronic Plus. I haven't really figured out why Distronic Plus isn't always activated when pulling the stalk towards me (or up/down).
Sometimes Speedtronic gets activated instead.
Is there an issue with the Distronic Plus or are there specific conditions Distronic Plus doesn't work?
How do I switch from Speedtronic to Distronic Plus?

It does work, and activates Distronic Plus most of the time, but sometimes it shows up Speedtronic instead.

Thank you!

How to use Distronic Plis:

As far as I know, depending on the market DISTRONIC has two modes. Cruise control mode and speed limiter mode (LIM/Speedtronic). I believe you toggle between the two by pressing on the button at the end of the stalk. You are probably accidently activating the LIM mode occasionally. It sets a maximum speed and then you can't accelerate past that speed unless you fully press through on the throttle pedal. Your instrument cluster should visually indicate if you are in CC or LIM mode. I think the LIM/Speedtronic mode is not something that is on US spec cars. I don't have it in my 2019 C63 for example. I've driven some cars with it, and I always found it confusing.